org.apache.solr.client.solrj.impl.LBHttp2SolrClient Maven / Gradle / Ivy
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* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
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* limitations under the License.
*/
package org.apache.solr.client.solrj.impl;
import java.util.Arrays;
import org.apache.solr.client.solrj.SolrClient;
/**
* LBHttp2SolrClient or "LoadBalanced LBHttp2SolrClient" is a load balancing wrapper around
* {@link Http2SolrClient}. This is useful when you
* have multiple Solr servers and the requests need to be Load Balanced among them.
*
* Do NOT use this class for indexing in leader/follower scenarios since documents must be sent to the
* correct leader; no inter-node routing is done.
*
* In SolrCloud (leader/replica) scenarios, it is usually better to use
* {@link CloudSolrClient}, but this class may be used
* for updates because the server will forward them to the appropriate leader.
*
*
* It offers automatic failover when a server goes down and it detects when the server comes back up.
*
* Load balancing is done using a simple round-robin on the list of servers.
*
* If a request to a server fails by an IOException due to a connection timeout or read timeout then the host is taken
* off the list of live servers and moved to a 'dead server list' and the request is resent to the next live server.
* This process is continued till it tries all the live servers. If at least one server is alive, the request succeeds,
* and if not it fails.
*
* SolrClient lbHttp2SolrClient = new LBHttp2SolrClient(http2SolrClient, "http://host1:8080/solr/", "http://host2:8080/solr", "http://host2:8080/solr");
*
* This detects if a dead server comes alive automatically. The check is done in fixed intervals in a dedicated thread.
* This interval can be set using {@link #setAliveCheckInterval} , the default is set to one minute.
*
* When to use this?
This can be used as a software load balancer when you do not wish to setup an external
* load balancer. Alternatives to this code are to use
* a dedicated hardware load balancer or using Apache httpd with mod_proxy_balancer as a load balancer. See Load balancing on Wikipedia
*
* @lucene.experimental
* @since solr 8.0
*/
public class LBHttp2SolrClient extends LBSolrClient {
private Http2SolrClient httpClient;
public LBHttp2SolrClient(Http2SolrClient httpClient, String... baseSolrUrls) {
super(Arrays.asList(baseSolrUrls));
this.httpClient = httpClient;
}
@Override
protected SolrClient getClient(String baseUrl) {
return httpClient;
}
}